In power transmission units for transferring power between a drive engine and a transmission, comprising a hydrodynamic component and an engageable and disengageable clutch device which serves to bypass the transferring of power via the hydrodynamic component, normally different pressure chambers are provided. Two pressure chambers with corresponding connections are provided in the hydrodynamic component only for conveying process fluids, whereby it is also being to control the conveying of process fluids possible via the connections. A first pressure chamber is formed here by the working chamber of the hydrodynamic component, while the second pressure chamber is formed by the interspace between the housing and the hydrodynamic component. If a separate pressure chamber is provided in addition for pressurizing the actuating mechanism, in particular the piston element of the engageable and disengageable clutch device, the latter is also actuatable via a corresponding connection. Here it is necessary to seal the pressure chambers appropriately from each other, with the demand on the sealing devices being kept as small as possible. The individual sealing devices are normally fitted into corresponding grooves in elements bounding on the pressure chamber. Depending on the design of the power transmission unit, in particular the arrangement of the individual elements with respect to each other and the design of the individual pressure chambers and their connections with each other, this creates a very complicated design with regard to the grooves provided for the individual sealing devices, these grooves being matched to the sealing devices that are to be used. Forming grooves on disk-shaped elements requires that they have a minimum thickness.